No33 Owner's Manual - Mark Levinson

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DONOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.CAUTIONRISK OF ELECTRIC SHOCKDO NOT OPENCAUTION: TO REDUCE THE RISK OF ELECTRICAL SHOCK, DONOT REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE.REFER SERVICING TO QUALIFIED PERSONNEL.The lightning flash with arrowhead symbol, within an equilateral triangle, is intended toalert the user to the presence of uninsulated “dangerous voltage” within the product’s enclosurethat may be of sufficient magnitude to constitute a risk of electric shock to persons.The exclamation point within an equilateral triangle is intended to alert the user to thepresence of important operating and maintenance (servicing) instructions in the literatureaccompanying the appliance.Marking by the “CE” symbol (shown left) indicates compliance of this device with the EMC(Electromagnetic Compatibility) and LVD (Low Voltage Directive) standards of theEuropean Community.The information contained in the manual is subject to change without notice. The most current version of this manual willbe posted on our web site at http://www.madrigal.com.2

From all of us at Madrigal Audio Laboratories, thank you for choosing theMark Levinson Nº 33 Reference Monaural Power Amplifier.A great deal of effort went into the design and construction of this precisiondevice. Used properly, it will give you many years of enjoyment.4

Table of ContentsUnpacking the Nº33 ................................................................................... 6Handling the Shipping Crate ............................................................................ 6Unpacking Procedure ....................................................................................... 6Placement Considerations ........................................................................ 9Ventilation ........................................................................................................... 9Spiking the Amplifier ........................................................................................ 10Operating Voltage .................................................................................... 11Nº33 AC mains current requirements ..................................................... 12Nº33 rear-panel label ............................................................................... 12Special Design Features........................................................................... 13Massive Power Supply ..................................................................................... 13AC Regeneration ............................................................................................. 13Fully balanced design ..................................................................................... 14True Voltage Source ........................................................................................ 14Extensive Protection ........................................................................................ 15Front Panel ................................................................................................. 16Rear Panel ................................................................................................. 17Remote turn-on tip polarity ..................................................................... 20Care & Maintenance................................................................................ 23U.S. and Canadian Warranty ................................................................... 2490-Day Limited Warranty ................................................................................. 24Five Year Extended Warranty ......................................................................... 24Obtaining Service ..................................................................................... 25Specifications ............................................................................................ 26Dimensions: Nº33 ...................................................................................... 275

Your Mark Levinson ® Nº33 power amplifiers incorporate heavy duty castersto facilitate their movement. If your flooring is even slightly fragile, be advisedthat significant pressure is generated by the Nº33’s approximately 350pounds (160 kg) being supported by four round casters. Before you removethe Nº33 from its shipping crate’s base, you may want to take measures toprotect delicate flooring from possible damage.With two people at the front of the amplifier to support its weight, carefullyslide the amplifier forward. (A third person may be needed to hold thecrate bottom in place as the amplifier is slid forward.) As the front castersclear the front edge of the crate, the two people in front must begin to supportthe weight of the front half of the amplifier. There is a “handle” builtinto the sculpted faceplate for this purpose, just above the Mark Levinsonlogo. Alternatively, you may also grip the front heatsinks. While supportingthe front of the amplifier, continue sliding the amplifier forward until thecenter section of the amplifier has cleared the edge of the crate’s base. Thefront of the amplifier may then be lowered gently to the floor.With the amplifier supported by the floor in the front and the crate in therear, both people should move to the rear of the amplifier. Gripping the rearheatsinks, lift the rear end of the amplifier and slide the base of the crateaway. (A third person is helpful in this, if available.) Gently lower the rear ofthe amplifier to the floor, allowing it to come to rest on its casters.Congratulations. The hard part is over.After unpacking your Nº33 power amplifiers, keep all packing materials forfuture transport. Shipment of the amplifier without the original packing materialwill almost certainly result in damage to the amplifier, and is not recommended.Locate and remove all accessory items from the accessory cartons. Accessories foreach amplifier include:4 machined aluminum spiked “feet”Carefully inspect your amplifier for possible damage. If you discover any, see yourMark Levinson dealer immediately.Important:When it comes to high current AC wiring such as the Nº33 willtypically use, building regulations and electrical codes varyfrom region to region (sometimes even from one municipalityto the next). For this reason, it is impossible for us to anticipatethe requirements of your area with regard to high current AChookups. Please review this manual’s section on OperatingVoltage and contact a local electrical contractor for adviceon connecting your Nº33 to the AC mains power in your area.8

Placement ConsiderationsPRECAUTIONFor your protection, review “Important Safety Instructions” and“Operating Voltage” before you install your Nº33.Your Mark Levinson Nº33 power amplifiers are specifically designed to stand onthe floor, and must be used as freestanding units. In most installations, locatingthem near the loudspeakers is best. Obviously, this approach minimizes thelength of the speaker wires and necessitates longer interconnecting cables fromthe preamplifier to the power amplifiers. The advantage to this strategy lies in thefact that the interconnecting cables carry low-current signals which are morereadily transmitted over distances with great accuracy than are the necessarilyhigh current signals required by loudspeakers.Note that adequate clearance for the AC cord and connecting signal cables mustbe left behind each Nº33. We suggest leaving at least six inches (15 cm) of freespace behind each Nº33 so that all cables have sufficient room to bend withoutcrimping or undue strain.Each amplifier should also be placed in such a way that the power switch on therear panel is easily accessible. This switch disconnects power from even the supervisorypower supply, resulting in effective disconnection of the amplifier fromthe AC mains. (Note that under these conditions, the amplifier cannot respond toremote-turn-on commands, etc.)VentilationYour Mark Levinson Nº33 power amplifiers have been designed to complementyour listening room visually, with a tall and narrow frontal area which reducestheir effective “footprint” and makes them far more presentable than would bethe case with a more traditionally proportioned design. As a result, they can bemore easily placed beside your loudspeakers. As freestanding units, the Nº33 amplifiersnormally will have no problem with ventilation.Each of your Nº33 power amplifiers dissipate approximately 800 watts of energyas heat when “at idle.” It is therefore normal and perfectly safe for them to runwarm. They do, however, require free air flow around them to allow adequateheat dissipation through air circulation. The top plate and heatsinks of the Nº33must be kept free from any obstruction which would reduce the free flow of air.If your amplifier must be located inside an enclosure of some sort that restrictsairflow, we strongly advise using some fans to increase ventilation through theenclosed space. If the amplifiers become too warm to touch, they are receivinginadequate ventilation. While they are fully protected against overheating, no oneenjoys interrupted listening sessions.Mechanical drawings are included in this manual to facilitate special installationsand custom enclosures where necessary (see “Dimensions” at the end of thismanual).9

Operating VoltageYour Mark Levinson Nº33 Reference Monaural Power Amplifier is characterized byits remarkable ability to pass a musical signal with utter integrity, regardless ofhow demanding that signal and the loudspeakers used might be. When calledupon to do so, the Nº33 is capable of generating truly prodigious power levelsinto virtually any speaker load, on either an instantaneous or a continuous basis.Depending on the demands placed on the Nº33 by your loudspeaker and yourlistening habits, it is possible for the quality and current capability of your electricalservice to become the limiting factor in the performance of your system.Given its status as a Reference product, any such limitation (even if only rarelyencountered) is unacceptable. As a result, the Nº33 has been designed to be capableof taking advantage of dedicated high current AC mains supplies whichcannot limit its performance. The Nº33 may be ordered in either a High Current(HC) or an Ultra High Current (UHC) configuration, depending on the requirementsof any given installation. (Due to CE regulations, only the UHC, 230V versionof the Nº33 is available in European Union countries.)The UHC configuration of the Nº33 accepts a dedicated high voltage (200–240volts, depending on the country), high current (30–35 amperes, depending onlocal electrical codes) AC power source. These high current lines are commonlyused in residential construction for electric stoves, clothes driers, and other demandingappliances, making their installation fairly routine for any electrical contractor…although this may be the first time your contractor has installed suchlines for a stereo system!Important:When it comes to high voltage/high current AC wiring such asthe Nº33 may use, building regulations and electrical codesvary from region to region, and even from one municipality tothe next. For this reason, it is impossible for us to anticipate therequirements of your area with regard to high current AChookups. Please review this section carefully and thencontact a local electrical contractor for advice onconnecting your Nº33 to the AC mains power in your area.The Mark Levinson Nº33 amplifiers may be factory-set for 100V, 120V, 200V, 210V,220V, 230V or 240V AC mains operation at either 50 or 60Hz. Depending on localelectrical codes and regulations, the plug on the supplied AC input module mayneed to be replaced by a local, licensed electrical contractor. The maximum currentrequirements at these various voltages under various test conditions arelisted in the table shown on the next page.11

Nº33 AC mainscurrent requirements100V 120V 200V 210V 220V 230V 240VOff

Special Design FeaturesCongratulations on your purchase of Mark Levinson Nº33 Reference MonauralPower Amplifiers. While your new amplifiers are straightforward in their everydayuse, they include several design features which are responsible for their outstandingperformance. In particular, the Nº33 Reference Monaural power amplifiersdefy the accepted wisdom that it is impossible to design a large, powerful amplifierthat also has all of the finesse of the finest smaller amplifiers. A few of thetechnical highlights that make this possible are given below.Massive Power SupplyThe Nº33 incorporates two 2.45 kVA low noise toroidal transformers in a fullybalanced power supply. In this design, there is a separate power supply (eachwith its own power transformer) for both the inverting and non-inverting halvesof the amplifier. Twelve 39,000 µF low ESR capacitors are used in each amplifier.The power supply of each Nº33 provides almost 1 ⁄2 a Farad of capacitance and1200 Joules of energy storage.Heavy oxygen-free copper bus bars enhance the efficiency of power distributionwithin the amplifier and eliminate variances introduced by the wiring harnesses,etc. more commonly found even in high performance amplifiers. High frequencypower supply bypass is accomplished on individual PC boards by a total of 56components of several film types. The resulting uniformly low power supply impedanceseen by the various circuits within the Nº33 lays the foundation for boththe massive power and the extraordinary finesse that characterizes this amplifier.AC RegenerationIn recent years, the detrimental sonic effects of noisy, unbalanced AC mains supplieshave become widely known. Various passive AC “line conditioners” are availablefor use with line level components such as preamplifiers and digital audioprocessors to address these problems. In most cases, these line conditioners providesome filtering of the AC mains, along with some measure of surge protection.None of these devices may be used to good effect with power amplifiers,however, since they cannot handle the large instantaneous currents which poweramplifiers require during normal operation. In effect, passive line conditionersbecome a “bottleneck” in the otherwise free flow of power through the amplifierto the speakers, reducing dynamic impact and musicality.In the Nº33, a more sophisticated approach is used that provides greater line conditioningbenefits than the commercially available passive devices can hope toprovide, while simultaneously avoiding any performance “bottlenecks.”A distortion-free 60 Hz sinewave is regenerated within the Nº33, and then usedto power a separate power supply dedicated to all the voltage gain stages. ACpower is delivered from the wall to the primary supply of the Nº33, where it isrectified, filtered and regulated into positive and negative DC voltages. A portionof this DC power is then used to drive an oscillator circuit which regenerates apure 60 Hz sinewave without any of the noise or contamination so common tothe AC mains as delivered to our homes by power utilities.The regenerated, pure sinusoidal AC wave is then sent to a dedicated secondarypower supply, where it is converted to positive and negative DC power to beused by all of the voltage gain stages. This dedicated supply for voltage gainstages benefits from having a truly balanced source (unlike the dissimilar imped-13

ances of AC mains line and neutral), as well as from the total elimination of ACmains fluctuations and noise. As a result, the critical voltage gain stages of theNº33 operate in a highly optimized environment, and are able to pass along significantlymore low-level resolution and detail in the musical signal that they amplify.Fully balanced designA truly balanced input topology eliminates the need for an input buffer amplificationstage and allows the first stage differential amplifier to be driven directly bythe source. Matched impedances are presented to the source and both signalstravel through identical circuit paths. Voltage gain is implemented on a cyanateester circuit board for superior sonic performance and consistency.Painstaking attention to layout of the amplifier was essential to minimize magneticfield distortions possible with such a massive power delivery system, includingcareful mirror-imaging of circuits to cancel magnetic fields. Balanced output isaccomplished through the use of two identical amplifiers. A balanced input signalremains balanced throughout the Nº33. Rejection of common mode noise anddistortion is obtained when the two halves finally meet: in the loudspeaker’svoice coil.True Voltage SourceThe Nº33 power amplifier operates as a virtually perfect textbook case of a “voltagesource.” This is to say that the Nº33 will maintain whatever the appropriatevoltage might be at any moment (given the demands of the music) without anyparticular regard for the current demands of the loudspeaker. Whether the loudspeakerrequires one amp or one hundred amps of current at that instant, theNº33 will deliver it.Because of this “voltage source” characteristic, the Nº33 doubles its power outputevery time the loudspeaker impedance is cut by half. Its continuous rated poweris 300 watts at 8Ω; 600 watts at 4Ω; 1200 watts at 2Ω; and 2400 watts at 1Ω—assuming the electrical circuit in the wall can support these extraordinary powerlevels. A 1Ω test at continuous maximum power requires about 62 amperes at120V and 31 amperes at 240V. (The laws of physics refuse to be cheated. Longterm,you cannot deliver more power into the speaker than you can pull from thewall.)Sixty TO-3 output transistors are distributed in the four main heatsinks of eachNº33 to conduct and control the flow of its prodigious power capabilities to theloudspeaker. There are fifteen complementary pairs of output transistors in eachof two output stages (inverting and non-inverting) within each amplifier.No known loudspeaker can absorb the continuous full power capability of theNº33. (Nor would you want to be present in the room were you to find one thatcould do so.) However, many high quality loudspeakers may require these ratherextreme power levels on a short term basis when reproducing music at realisticlevels. The Nº33 can answer these needs with impunity, without any power supply“sag” and without altering its sonic performance in any way. Its resultant imperturbablenature is reflected in the authority and control with which it reproducesmusic.Extensive ProtectionYour Nº33 power amplifiers will shut themselves down if they sense any of anumber of fault conditions which could cause damage to either themselves or toyour loudspeakers. These fault conditions include14

• the presence of DC (direct current) at the output• either over-voltage or under-voltage conditions on the AC mains• unsafe operating temperatures in any of several critical areaswithin the amplifier• sustained output current in excess of 80 amperes (which wouldoccur only in the event of a dead short across the outputs).If any of these fault conditions is sensed while the amplifier is in either standbyor fully on, the amplifier will shut down completely (off mode, not merelystandby). Moreover, it will not turn on again until the fault condition is corrected.In addition, the AC input to each transformer is fused to protect against excessivecurrent conditions such as driving shorted outputs. In-rush limiting prevents prematureaging of power supply components during power-up, and switches offlineonce the power supply has been charged.Finally, the Nº33 incorporates a controlled clipping circuit that prevents the outputdevices from saturating. The harsh high frequency harmonics generated by hardclippedoutput devices are avoided by the waveshaping action of this controlledclip circuitry.15

MADRIGAL AUDIO LABORATORIESRREFERENCEMONAURAL 2AMPLIFIERNº 331Front Panel1 STANDBY BUTTONWhen power is first applied to the Nº33 power amplifier, and assuming therear panel AC mains switch is set to its on position, the amplifier remainscompletely off. Pressing the front panel standby button will bring the amplifierfrom completely off to standby. After a delay of ten seconds (to allowall circuitry to stabilize), subsequent pressing of the power button willtoggle the Nº33 between standby mode and fully on. Power consumptionof the Nº33 when fully on and at idle is approximately 600 watts.To turn the amplifier completely off, press and hold the standby button forapproximately one second, until the front panel indicator light turns off.2 INDICATOR LIGHTThe indicator light shows the operational status of your Nº33:Full brightness indicates that the Nº33 is on and ready to be used.Blinking slowly indicates the unit is in standby.Dimly lit indicates that the main power supply is completely off, leavingonly the supervisory supply operational.Completely off indicates that the rear panel AC mains switch has beenturned off, disengaging even the supervisory power supply.If the amplifier will not turn on, you may want to check the rear panel ACmains switch , your AC connections, or have your dealer inspect the rearpanelfuses (which are not user-serviceable).16

slave outslave inPUSHremote turn-on jacksc o m m u n i c a t i o n s p o r t s12345Rear PanelCaution!Turn the volume on your preamplifier all the way down beforeattempting to connect anything to your Mark Levinson Nº33.1 SINGLE-ENDED INPUTSThese RCA connectors accept single-ended inputs from preamplifiers withsingle-ended (RCA) outputs. Both inverting and non-inverting inputs areprovided. Single-ended input signals are converted to balanced signals immediatelyupon being received at the Nº33, and are handled as balancedsignals thereafter.If your preamplifier does not support balanced connection to the poweramplifier, connect the single-ended output of your preamplifier to the noninvertingRCA input on the Nº33. Repeat this process for the other Nº33(s)in your system, being certain to be consistent throughout. To reduce thechance of noise pickup at the (otherwise unterminated) inverting input,short the inverting input of each amplifier by inserting the provided U-shaped shorting strap between pins #1 and #3 of the XLR connector to reducethe chance of noise pickup at the (otherwise unterminated) input. (Asdelivered from the factory, this shorting strap is already installed.)Important!If you use single-ended interconnection with the Nº33, youmust take care to use one input or the other (inverting or noninverting)consistently throughout your system. If you mix their17

use, the amplifiers will operate out of phase with each other,resulting in a loss of bass and poor imaging.Although the best form of balanced interconnection is via a balanced cableand XLR connectors, it is possible to operate the Nº33 in a balanced configurationby using both inverting and non-inverting RCA inputssimulataneously. This approach is generally less desirable, however, sinceseparate single-ended cables will be more susceptible to noise pickup thana single balanced cable. If this approach is taken, you must remove theshorting strap from the XLR input. Save it for possible use at a later date.2 BALANCED AUDIO INPUTAccepts a signal from a preamplifier with balanced outputs via a high qualityXLR connector. If connection to the preamplifier is made with a balancedinterconnecting cable, it is important to remove the shorting plugfrom between pins #1 and #3 of the XLR input which was placed thereprior to shipment from the factory. Save it for possible use at a later date.The pin assignments of this XLR-type female input connector is:PUSH2 13Pin 1: Signal groundPin 2: Signal + (non-inverting)Pin 3: Signal – (inverting)Connector ground lug: chassis groundThese pin assignments are consistent with the standards adopted by theAudio Engineering Society. Refer to the operating manual of your balancedoutputpreamplifier to verify that the pin assignments of its output connectorscorrespond to your Mark Levinson Nº33. If not, wire the cables so thatthe appropriate output pin connects to the equivalent input pin.3 COMMUNICATIONS LINK AND REMOTE TURN-ON INPUTSThe Nº33 may be controlled by a “linked” Mark Levinson 30-series preamplifierwhen the slave in communications port is connected to the masterport of the preamplifier. Subsequent Nº33 amplifiers may be “daisy chained”from the first Nº33’s slave out to their slave in port, up to a maximum ofsix amplifiers total.slave outslave inremote turn-on jacksc o m m u n i c a t i o n s p o r t sA “straight-through,” six conductor Link cable with six-conductor modularconnectors on both ends is used to connect the preamplifier to the firstpower amplifier. Such a cable is made (counter-intuitively) by incorporatinga 180° twist into the cable before terminating it, as shown below:18

displayintensitypolarityinvertdisplayintensitypolarityinvertaes/ebuemphasis1 2 3 4 5 6aes/ebuemphasismode1 2 3 4 5 6MADRIGAL AUDIO LABORATORIESREFERENCEMONAURALAMPLIFIERNº 33Rmodeteach irteach irMADRIGAL AUDIO LABORATORIESREFERENCEMONAURALAMPLIFIERNº 33MADRIGAL AUDIO LABORATORIESCOMPACT DISC DRIVENº 37standbyMADRIGAL AUDIO LABORATORIESDIGITAL PROCESSORNº 36standbyMADRIGAL AUDIO LABORATORIESPREAMPLIFIERNº38RstandbyRRRTo Nº38 MasterTo Nº33 Slave InLocking tabLocking tab(any Mark Levinson transport)slave outA different Link connector configuration is used for the “daisy-chain” of oneamplifier to the next, to minimize the opportunity for mis-wiring. In effect,this cable is identical to the one between preamplifier and power amplifierexcept that it uses pins 1 through 6 of an eight-conductor modular connectorat one end, as shown below:digital outputslave inNº36digital inputanalog outputLinkcablemasterTo Nº33 Slave OutLocking tabTo Nº33 Slave InLocking tab(Note that the pins are numbered 1 through 8 from left to right when thelocking tab is down and the metal contacts are pointing away from you.)Nº38any inputLinkcableslavemasterLinkcableslave inWhen connected in this manner, the power amplifiers will be toggled betweenstandby and fully on when the preamplifier goes between standbyand fully on. In addition, should a fault condition cause the amplifier’s protectioncircuitry to activate, the Nº33 can report the nature of the problemto a linked Mark Levinson preamplifier via this communications link. If thisoccurs, the preamplifier will display the number of the amplifier at fault(AMP1 being the first amplifier in the daisy chain, AMP2 being the secondamplifier, and so on). The preamplifier will also indicate the nature of thefault condition with one of the following codes:CodeHOT!DCO!ZAP!Fault Conditionthermal shutdownuncorrectable DC offsetexcessive output currentNº33slave inLinkcableslave outAdditional remote turn-on jacks provide compatibility with a wide range ofproducts, to facilitate remote turn-on and turn-off in systems which do notinclude a Mark Levinson 30-series preamplifier (which would normally usethe Mark Levinson Communications Link described above). These 1 ⁄8" (3.5mm) “mini-jacks” allow other components to bring the Nº33 power amplifiersin and out of standby. Two such mini-jacks are provided to allow“daisy-chaining” of multiple amplifiers. When “daisy-chaining” multiple amplifiers,the last mini-jack in the chain must be terminated with a dummy1⁄8" plug [that is, an empty plug must be inserted into the 1 ⁄8" (3.5 mm)jack].This remote “trigger” will be operated by a 3–12 volts DC positive-polaritypulse, of at least 100 milliseconds duration, with tip polarity as shown below:Remote turn-on– +tip polarity3-12 volts for atleast 100 mS19

Your Mark Levinson dealer can help you take advantage of these designfeatures to maximize your system’s versatility.4 SPEAKER BINDING POSTSThe Mark Levinson Nº33 is equipped with custom made, gold-plated, highcurrentbinding posts for output termination to a loudspeaker system. Totake full advantage of the Nº33’s sonic quality, we recommend using highqualityspeaker cable; see your Mark Levinson dealer.Caution!NEVER connect the Mark Levinson Nº33 output terminals toany device other than a loudspeaker.NEVER short-circuit the amplifier's output terminals.NEVER connect the output terminals of one amplifier to theoutput terminals of another amplifier.We recommend connecting speaker cables to the Mark Levinson Nº33bymeans of a high-quality spade lug or hook lug, soldered to the cable (orcrimped with extremely high pressure).Spade lugHook lugConnect a + (positive or red) output post of the Mark Levinson Nº33 to the+ (positive or red) input terminal of the appropriate loudspeaker. [Ifbiwiring, repeat using the other + (positive or red) output post of the amplifierand the + (positive or red) input terminal of the loudspeaker.]Connect a – (negative or black) output post of the Nº33 to the – (negativeor black) input terminal of the appropriate loudspeaker. [If biwiring, repeatusing the other – (negative or black) output post of the amplifier and the –(negative or black) input terminal of the loudspeaker.]5 AC MAINS CORD AND AC MAINS SWITCHConventional IEC standard power cords cannot be used in the Nº33, due tothe potential current requirements of Nº33 when operating into low impedanceloads. (The highest available current rating for an IEC standard threeconductorconnector such as is used on most stereo equipment, includingother Mark Levinson products, is 16 amperes.) Instead, the Nº33 incorporatesa high current AC cord which is attached directly to the amplifier itselfvia a specially-designed AC mains module, located at the bottom of the rearpanel. A high current AC connector is included with the Nº33 and may beattached to the end of the AC mains cord.20

Warning!High current AC wiring regulations vary from one location toanother—do not attempt to connect the Nº33 to your ACmains power without consulting a qualified local electricalcontractor. (See Operating Voltage in this manual for moreinformation.)The Mark Levinson Nº33 has been safety-tested and isdesigned for operation with a three-conductor power cord.Do not defeat the “third pin” or earth ground of the AC powercord.An AC mains switch is located adjacent to the power cord on the rearpanel of the amplifier. This switch may be used to disconnect the supervisorypower supply from the AC mains without having to actually unplug theamplifier from the wall outlet. Since this small supervisory supply controlsthe main power supply’s access to AC power, shutting down the supervisorypower supply also disconnects the main supply from AC. If you plan to beaway for an extended period, or have any other reason to turn the amplifiercompletely off, you may use the AC mains switch.Note:When first connected to the AC mains, the amplifier normallydraws a small amount of power which is used to control thepower-up sequence. Turning this rear panel switch “off”disconnects even this small power supply; you must turn thisswitch back “on” before you can enter the power-upsequence described in Front Panel, item #2, or before theamplifier will respond to a remote turn-on command.Two slo-blow 35 ampere fuses are located inside the Nº33, on the AC mainsmodule. The protection circuitry of the Nº33 has been designed such thatonly a catastrophic failure could cause these fuses to blow. As a result, ifyou suspect that your AC fuses have blown, disconnect the Nº33 from theAC mains and contact your Mark Levinson dealer for assistance. Do not attemptto replace these fuses yourself.Danger!Potentially dangerous voltages and current capabilities existwithin the Nº33 power amplifier, even when disconnectedfrom AC mains. Do not attempt to open any portion of theNº33’s cabinet.There are no user-serviceable parts inside the Nº33 poweramplifier. All service of this product must be referred to aqualified Mark Levinson dealer or distributor.21

Care & MaintenanceTo remove dust from the cabinet of the Nº33, use a feather duster. To remove dirtand fingerprints, we recommend isopropyl alcohol and a soft cloth. Apply the alcoholto the cloth first and then lightly clean the surface of the Nº33.Caution!At no time should liquid cleaners be applied directly to theNº33, as direct application of liquids may result in damage toelectronic components within the unit.22

U.S. and Canadian Warranty90-Day Limited WarrantyThis Mark Levinson ® product is warranted to be free from defects in material andworkmanship under normal use for a period of ninety (90) days from the date ofpurchase. To extend the warranty of this Mark Levinson product, return the warrantyregistration card along with a copy of the original receipt of purchase toMadrigal Audio Laboratories, Inc., P. O. Box 781, Middletown, CT 06457.Five Year Extended WarrantyThe extended warranty for this Mark Levinson product is five (5) years from thedate of purchase. During the warranty period, any Mark Levinson component exhibitingdefects in materials and/or workmanship will be repaired or replaced, atour option, without charge for either parts or labor, at our factory. The warrantywill not apply to any Mark Levinson component that has been misused, abusedor altered.Any Mark Levinson component not performing satisfactorily may be returned tothe factory for evaluation. Return authorization must first be obtained by eithercalling or writing the factory prior to shipping the component. The factory willpay for return shipping charges only in the event that the component is found tobe defective as above mentioned. There are other stipulations that may apply toshipping charges.There is no other express warranty on this component. Neither this warranty norany other warranty, express or implied, including any implied warranties of merchantabilityor fitness, shall extend beyond the warranty period. No responsibilityis assumed for any incidental or consequential damages. Some states do not allowlimitations on how long an implied warranty lasts and other states do notallow the exclusion or limitation of incidental or consequential damages, so thatthe above limitation or exclusion may not apply to you.This warranty gives you specific legal rights, and you may also have other rightswhich vary from state to state. This warranty is applicable in the United States andCanada only. Outside of the U.S. and Canada, please contact your local, authorizedMark Levinson distributor for warranty and service information.23

Obtaining ServiceWe take great pride in our dealers. Experience, dedication, and integrity makethese professionals ideally suited to assist with our customers’ service needs.If your Mark Levinson component must be serviced, please contact your dealer.Your dealer will then decide whether the problem can be remedied locally, orwhether to contact Madrigal for further service information or parts, or to obtaina Return Authorization. The Madrigal Technical Services Department worksclosely with your dealer to solve your service needs expediently.Important!Return authorization must be obtained from Madrigal’sTechnical Services Department BEFORE a unit is shipped forservice.It is extremely important that information about a problem be explicit and complete.A specific, comprehensive description of the problem helps your dealer andthe Madrigal Technical Services Department locate and repair the difficulty asquickly as possible.A copy of the original bill of sale will serve to verify warranty status. Please includeit with the unit when it is brought in for warranty service.Warning!All returned units must be properly packaged (preferably intheir original packing material), and the proper returnauthorization numbers must be marked on the outer cartonfor identification. If the packaging to protect the unit is, in ouropinion or that of our dealer, inadequate to protect the unit,we reserve the right to repackage it for return shipment at theowner’s expense. Neither Madrigal nor your dealer can beresponsible for shipping damage due to improper (that is,non-original) packaging.Your dealer can order a new set of shipping materials for you if you need to shipyour component and no longer have the original materials. There will be acharge for this service. We strongly recommend saving all packing materials incase you need to ship your unit some day.24

SpecificationsThe correlation between published specifications and performance is unreliable. Alist of numbers reveals virtually nothing. All technical measurements must be subjectto qualitative as well as quantitative interpretation. Measurements of the MarkLevinson Nº33 yield excellent results by any standards. However, only those specificationsthat apply to its actual operation are included here. All specifications aresubject to change at any time, in order to improve the product.■ Rated power output: 300 w/ch continuous rms power @ 8Ω600 w/ch continuous rms power @ 4Ω1200 w/ch continuous rms power @ 2Ω2400 w/ch continuous rms power @ 1Ωall of the above power ratings measured from20 Hz–20 kHz with no more than 0.3% THD■ Frequency response: within 0.1 dB from 20 Hz to 20 kHz■ Signal to Noise ratio (main outputs): better than –80 dB (ref. 1 w)■ Input impedance: 100kΩ (balanced)50kΩ (single-ended)■ Voltage gain: 26.8 dB■ Input sensitivity: 2.3 V for full rated output■ Power consumption: typically 840 W (±5%) at idletypically 210 W (±5%) in standby■ Mains voltage: determined by the needs of country for whichthe unit was manufactured; cannot be reset by dealer or user■ Overall dimensions: See “Dimensions”■ Shipping weight: 435 lbs. (198 kg) each■ Connector complement: four custom binding posts per channelone 3-pin XLR balanced input connector per channeltwo RCA input connectors per channeltwo 1 ⁄8" mini-jacks for remote turn-ontwo Mark Levinson communications ports (RJ-11)one captive high current AC mains cord■ Output impedance: less than 0.05Ω from 20–20,000 HzFor more information, see your Mark Levinson dealer, or contact:Madrigal Audio Laboratories, Inc.P.O. Box 7812081 South Main Street (Route 17)Middletown, Connecticut 06457 USATelephone (860) 346-0896FAX (860) 346-1540Madrigal provides an owner-transferable, five year limited warranty on allMark Levinson products within the U. S. and Canada ONLY. Warranty andservice policies outside the U. S. and Canada are set by the local, authorizeddistributor and are applicable in the country of purchase ONLY. Madrigalproducts are designed to operate at set voltages appropriate for the countryof sale and may be damaged if operated at the wrong voltage.25

MADRIGAL AUDIO LABORATORIESRPUSHDimensions: Nº3312.75"32.3 cm2.875"7.3 cm7.0"17.8 cm2.875"7.3 cm5.0"12.7 cmREFERENCEMONAURALAMPLIFIERNº 3331.0"78.74 cm27.06"68.74 cm14.0"35.6 cm3.125"7.94 cm.81"2.06 cm9.75"24.8 cm30.0"76.2 cm 9.75"24.8 cm31.0"78.74 cm31.0"78.74 cm26

Madrigal Audio Laboratories, Inc.2081 South Main Street, P.O. Box 781Middletown, Connecticut 06457 USATelephone: (860) 346-0896Fax: (860) 346-1540http://www.madrigal.com/RMADRIGAL AUDIO LABORATORIESis a registered trademark of Madrigal Audio Laboratories, Inc.a Harman International company630133-5 © 6/1998 Madrigal Audio Laboratories, Inc. All rights reserved. Printed in U.S.A.